Liquid chromatography is a method for separating components within a sample by interaction between a moving bed (eluent) and a fixed bed which has an advantage of simultaneously measuring several components by injecting the sample once.
However, since all the components included in the sample are discharged through a column, the liquid chromatography method requires very long time and therefore may be hardly used for fast measuring only a specific material.
Describing, for example, ion chromatography which is one kind of the liquid chromatography, the ion chromatography differently represents a detection time and separation of ions according to characteristics of the column, but the separation is generally proportional to the detection time. That is, to improve the separation, the very long detection time is required.
When the sample including all the ions such as F—, CH3COO—, Cl—, NO2−, Br—, NO3-, and SO42- is analyzed by the ion chromatography method, in the case of the ions of F, CH3COO—, Cl—, a retention time in a currently commercialized column is similar and thus the detection time is also similar, such that characteristics of resolution thereamong may deteriorate.
Further, the SO42- which is one of the materials having a very late retention time is one of the most important ions determining an analysis time.
Even though only the F— and Cl— in the samples are an analysis species of interest, when the SO42- is present, the analysis time is determined by the detection time of the SO42-. The detection time of the SO42- in the sample is determined by the retention time of the column and when a subsequent sample is analyzed in the state in which the SO42- in the sample is introduced into the column and thus is not completely discharged, the SO42- affects an analysis of the subsequent sample and therefore the analysis is performed after the SO42- is completely discharged.
As one example of automation equipment, an ion chromatography analysis method used in a tele-monitoring system (TMS) for exhaust gas from a chimney is more excellent than an ion electrode method or a non-dispersive infrared method which is used in the related art, but takes a long analysis time and therefore may be hardly applied.
Since the exhaust gas from the chimney is managed by an environmental law of an effluent quality standard, a total quantity standard, and the like, performance of the TMS for exhaust gas from a chimney is legislated. One of the legislated performances of an analyzer is a response time and since in the case of the non-dispersive infrared method, the response time is 5 minutes and in the case of the ion electrode method, the response time is 10 minutes, in order for the ion chromatography to be used in the TMS, a very fast analysis of 10 minutes or so is required.
In particular, the exhaust gas from the chimney includes very various components in addition to a target material and since the components act as an intervening factor, there is a need to completely separate the components and perform the fast measuring of 10 minutes or so.
To solve the foregoing problems, the related art manually or automatically controls a kind of columns, a concentration or a composition of the moving bed, a flux of the moving bed, and the like to improve the resolution among F—, CH3COO—, and Cl— having a short retention time, but delays the detection of SO42- and thus may not reduce the total analysis time.
FIG. 1 illustrates that the separation is improved by controlling the concentration of the moving bed and it may be appreciated from FIG. 1 that the separation is improved, the analysis time is longer, and it takes 30 minutes or more due to a stabilization time required for subsequent analysis after the concentration of the moving bed is controlled.
As the related art, Korean Patent Application No. 2008-7009108 (filing date: Apr. 16, 2008, Title: Multidimensional Chromatography Apparatus and Method) uses a column switching method for removing a matrix from a sample but does not yet achieve reduction in an analysis time and improvement in separation.